Combination of CO2 storage and geothermal energy production in porous and fractured superhot geothermal systems

Abstract leakage is one of the main risks and barriers to geologic carbon storage. However, under the high‐temperature and high‐pressure conditions characteristic of superhot geothermal systems in deep volcanic regions, becomes denser than supercritical water. The sinking nature of in these systems creates a unique opportunity: enabling secure geological carbon storage while simultaneously harnessing geothermal energy. Here, we numerically simulate storage in 3D porous and fractured superhot geothermal reservoirs and examine the influence of fracture network properties, including fracture size and aperture. Simulation results indicate that, unlike homogeneous porous reservoirs, in which exhibits a pronounced downward migration, fractured reservoirs show a less distinct sinking behavior, with larger viscous forces than those in porous media because of the higher flux along the fracture network, resulting in more uniform water displacement. Additionally, reservoir cooling is found to be confined to a limited zone surrounding the injector across all investigated scenarios, limiting the risk of cooling‐induced seismicity.